Movement and population structure of cerambycid beetles (Coleoptera: Cerambycidae) and white-footed deermice (Peromyscus leucopus) on a fragmented forest landscape

Department: University of Delaware, Department of Entomology and Wildlife Ecology

Publisher: University of Delaware

Date Issued: 2016

Abstract: Cerambycid beetles (Coleoptera: Cerambycidae) locate suitable hosts and mates using both pheromones and plant volatiles, many of which have been identified and are now produced synthetically for trap lures. The range over which these lures attract cerambycids within a forest, and the tendency for cerambycids to move out of a forest in response to these lures, have not been previously explored to our knowledge. We conducted two field experiments using baited and unbaited flight intercept traps in northern Delaware to investigate these questions. Within forest fragments, traps that were 2 m from the baited trap, but not 10 or 20 m, captured more beetles than control traps suggesting relatively short-range and nonspecific attraction by these lures. In contrast, male Prionus laticollis (Drury), which were attracted by the female-produced sex pheromone 3,5-dimethyldodecanoic acid, were rarely caught in unbaited traps at any distance from baited traps. Baited traps attracted significantly more cerambycids than unbaited traps outside of the forest at distances up to 40 m from the forest edge, with catch generally decreasing between 8 and 40 m from the forest. Some cerambycids were caught in both baited and unbaited traps at all distances from the forest edge, indicating that at least some cerambycids disperse freely outside of the forest independent of any pheromone attractants. Our results provide context to previous studies that used these pheromone lures, and offer insights into the dispersal behavior of cerambycids.
Forest fragmentation and human development undoubtedly affect wildlife movement on a landscape, but this effect likely varies by species. We analyzed single nucleotide polymorphisms (SNPs) in two species of cerambycid beetles and in white- footed deermice (Peromyscus leucopus) to determine the population structure of these species on the same fragmented landscape in northern Delaware. White-footed deermice showed more population structure than either cerambycid species, indicating that cerambycids are more capable of movement among forest fragments. The cerambycid Xylotrechus colonus showed less population structure than Prionus laticollis, which may be explained by both dispersal ability and life history differences. Our study highlights the importance of using diverse study species to assess connectivity and movement on a human-dominated landscape.